I. Field of the Invention
This invention relates generally to heating, ventilating and air-conditioning (HVAC) systems, and more particularly to a refrigeration system incorporating one or more cold buffers and optionally at least one closed exchange loop for recovering heat energy from a heat transfer fluid and storing same for subsequent transfer to one or more hot buffers disposed on the high pressure side of the system.
II. Discussion of the Prior Art
In my earlier U.S. Pat. Nos. 4,382,368 and 4,633,676, there is described a heating and cooling system that utilizes three components, referred to as "energy handlers", "buffers", and "power packs", in a way that effects substantial energy savings when compared to present methods utilizing consumption of fossil fuel for heating and electrical energy for air conditioning.
The '368 patent describes a system including a refrigeration loop in which a refrigerant, such as Freon 22, is compressed in 20. its gaseous state and subsequently cooled in a condenser to convert the refrigerant to a liquid state and subsequently made to pass through an expansion valve and an evaporator to again change the liquid refrigerant back to a gas. Coupled in heat transfer relationship to the condenser coils are heat exchangers that are connected in circuit with one or more hot buffers for storing an energy transfer fluid, e.g., water, for later use as a hot fluid supply. Thus, rather than merely passing air over the condenser coils and dissipating the heat energy to the outdoor ambient, the fluid passed through the heat exchangers closely coupled to the condenser coils is heated for later use.
My U.S. Pat. No. 4,733,676 describes an energy transfer system for transferring energy from and to a source liquid, such as well water, so as to provide both cooling and heating. It, too, includes a refrigeration system having an evaporator, a compressor, a condenser and an expansion valve for extracting heat from the well water through the evaporator and dissipating the heat through the condenser. In this arrangement, water stored in "hot buffer" tanks is conveyed through a conduit and into heat transfer relationship with the condenser. Heat energy is extracted from the condenser and absorbed by the water for future use by one or more energy handlers.
The present invention is related to my earlier inventions reflected in the aforereferenced U.S. Pat. Nos. 4,382,368 and 4,633,676, but differs therefrom by recognizing that further energy savings may be realized by incorporating heat exchangers and buffers on the low or cold side of the refrigeration system. In this way, heat energy is conserved by transferring it from place to place and constantly reusing it. It is found that transferring energy is significantly less expensive and substantially more efficient than generating new heat energy such as by burning of natural gas or other fossil fuels. The efficiency of the system of the present invention is derived fundamentally from its philosophy or methodology. This philosophy, among other things: (1) allows multiple jobs to be done for about the cost of one, (2) utilizes energy normally wasted from other processes, (3) utilizes energy recovered from other sources, (4) incorporates components that specifically sized for the job to be done and are not compromised sizes as required by present equipment technology, (5) reduces the size of the compressor for peak demands because of the system's ability to store energy in buffers for delivery at a peak time, and (6) optionally, produces domestic hot water in addition to cooling and heating space.
One of the factors contributing to the lower installation cost of system constructed in accordance with the present invention is the fact that the compressor need not be sized to the peak energy demands of the building, but instead, to the average demand. The storage buffers and energy handlers (utilization devices) are sized to deliver the peak demands. Thus, for example, the compressor has the "off peak" time to "charge up" the storage buffers. Most prior art systems are sized to meet the peak demand, even though that demand may only occur a few times a year, if ever. This can be very expensive and wasteful because it requires the purchase and installation of very costly equipment and requires the user to pay the starting and running costs for oversized equipment for its entire lifetime.
An example of this feature is perhaps best personified by considering an installation in a church building. The compressor and the heat exchanges associated with the condenser and evaporator would have all week to "charge" an energy transfer fluid (water) in a storage buffer, allowing a less expensive but efficient heat exchanger to deliver the "peak load" for a few hours on the weekend.
Using the principles of the present invention, one may heat at night with energy removed during the day. Similarly, one may cool when the sun is entering an office from the South, but heat the rest of the time.